Farmscape for January 30, 2012   (Episode 4074)

The Director of Research with the Pipestone, Minnesota Veterinary Clinic suggests air filtration is the last missing link needed to achieve sustainable freedom from Porcine Reproductive and Respiratory Syndrome.

PRRS affects the reproductive performance of sows and causes respiratory disease in nursery and finisher pigs.

"Achieving Sustainable PRRSV Freedom in Swine Dense Regions: The Role of Air Filtration" was discussed earlier this month as part of the 2012 Banff Pork Seminar.

Dr. Scott Dee, the Director of Research with the Pipestone Veterinary Clinic in Pipestone, Minnesota, says in the swine dense regions of southern Minnesota and northern Iowa, where you could have 20 barns within a 4.7 kilometer radius, airborne transmission is key.

Clip-Dr. Scott Dee-Pipestone Veterinary Clinic:
We've done some work a number of years ago that showed at least out to 9.1 kilometers the virus could be recovered in the air from an infected population of pigs and there weren't any other barns within a 16 kilometer radius where other viruses could come from so it was a very isolated area and we knew that this particular virus we collected in the air had originated from our source population.

That's as far as we looked so it may be able to go farther.

Some of the conditions that are required for it to go via the airborne route, obviously you need an infected population to produce an aerosol, you need a susceptible population to receive the aerosol and then you need slow moving winds from the source to the at risk population.

You need gentle movement with the wind is what really helps keep this virus plume intact so it can move from site to site.

Dr. Dee says under laboratory conditions filtered barns have gone four years without becoming infected, while under commercial conditions in very dense regions, boar studs that have been filtered for about six years have remained PRRS free while filtered sow facilities have remained free of infection for going on to three years.

For Farmscape.Ca, I'm Bruce Cochrane.

       *Farmscape is a presentation of Sask Pork and Manitoba Pork Council